About retina displays and resolution, etc

[Italianblend]

iphone 8 lists: 1334-by-750-pixel resolution at 326 Ppi
8+ lists: 1920-by-1080-pixel resolution at 401 ppi

I'm not an expert. I kind of get that the resolution will be different because the screen is a different size. The PPI has me a little confused. If it's a retina display, why would there be a difference in screen quality?

In other words, how can an image be clearer on an 8 plus as compared to an 8 and they're both the retina display, which is supposed to mean that you can't Differentiate pixels? Wouldn't they be the same quality?

 

[heov]

Retina is just a marketing term by Apple that means really small pixels (300+ or so ppi).

The iPhone 8 has 326ppi. The iPhond 8+ has 401ppi.

The iPhone 8+ has smaller pixels, and thus "more" retina than the 8. Though most users can't distinguish this difference.

Retina is by no means a technical term... it just means small enough. Apple uses "retina" in their MacBooks and iMacs as well. I believe Apple uses "Super Retina" for the X. Again, this is all marketing- not a technical specifications. It doesn't specific a specific ppi, just that it's high compared to phone screens from 5 years ago. I don't think you can even buy "non retina" phones from either camp these days... 326ppi is actually quite low for a phone these days.

 

[akash.nu]

The only scientific thing here is that on average most people can’t differentiate pixels over 300 ppi.

Apple calls any display “retina”, as long as it’s over that threshold. This was introduced with the iPhone 4.

 

[Jetcat3]

It’s also important to remember that “Retina” usually specifics a specific distance. In the case of the 8, it’s 10.5” away from the user’s face. The 8 Plus is 8.6” away. Because of this two inch difference there is a noticeable difference in sharpness of the 8 Plus over the 8.